The importance of intermediate alpha-1-antitrypsin deficiency (IATD) in the development of cardiopulmonary disease and more particularly the sequential changes leading to emphysema, will be studied by serial, prospective, detailed lung function tests including flow-volume, spirometry, plethsymography, washout, N2, and 133 Xenon ventilation and perfusion scans in approximately 200 subjects with IATD and a control group matched for age and smoking history from a normal, healthy population. AT will be quantitated by radial immunodiffusion and phenotypes determined by acid starch gel crossed immunoelectrophoresis. Family studies will also be done. The hypothesis that IATD may be a factor in lung damage associated with cardiac disease and more particularly with disorders of plasmin and thrombin inhibition will be tested. All patients seen in our cardiac catheterization and pulmonary function laboratories will have determinations of AT; IATD patients will be compared with controls matched for degree and type of cardiac disease, age and smoking history. Additionally, patients with IATD and matched controls having cardiopulmonary bypass surgery will have detailed pre and post operative pulmonary studies, using our physiologic monitor system to assess pulmonary function changes. Routine clinical clotting factors, serum proteolytic activity and inhibition, and AT levels will be measured serially during and after bypass. Biopsies of lung tissue will be examined by light of electron microscopy and immuno-fluorescent techniques. Labelled AT and fibrinogen will be given preoperatively and pulmonary deposition and clearance and localization in tissue biopsies determined. The effect of trasylol (a bovine inhibitor) on pulmonary complications of cardiac surgery and other acute pulmonary diseases in patients with IATD will be studied in a double blind manner. Use of estrogens and steroids, which stimulate production of AT will be studied in patients with COPD associated with ATD.